These lath martensite first nucleates in parent austenite intergranular and twin boundary.应变诱发马氏体首先在原奥氏体晶界和孪晶界形核.The microstructure of the weld zone is tempered martensite zone.热影响区的显微组织主要为回火马氏体;熔合线结合良好,组织均匀.There occour...